beautypg.com

The square wave – Waldorf Pulse 2 User Manual

Page 48

background image

Sound Synthesis Basics

Pulse 2 User Manual

48

Additive components of the Sawtooth wave

The sawtooth wave was thought as an abstraction of the
timbre of string and brass instruments. You can easily
understand that when you think of a violin. Imagine a
bow pulling the string slightly into one direction. At one
point, the string abruptly comes off the bow and swings

back to its original position. The bow is still moved and
so it catches the string again and the procedure is repea-
ted. The result is a waveform that looks like a sawtooth.
The same is true for a brass instrument. The string in this
case are the lips while the bow is the air. The lips are
moved by the air to a certain extent and abruptly move
back to their original position.

The Square Wave

The Square Wave is a pulse waveform with 50% pulse
width. This means that the positive part of the waveform
has the same length as the negative part. The pulse
waveform can have other pulse widths as you will read
later. For now, we´ll talk about the square wave as a
unique waveform. The square wave consists of all odd
harmonics in which the magnitude of each harmonic
descends by the factor of its position. This means that
the first harmonic has full magnitude, the third harmonic
has a third magnitude, the fifth harmonic has a fifth
magnitude and so on. The following picture shows how
the individual harmonics build up the pulse wave:

1

4

8

12

16

Frequency

Magnitude

Time

Amplitude

+

=

1st Harmonic

Magnitude 1

2nd Harmonic

Magnitude 1/2

3rd Harmonic

Magnitude 1/3

4th Harmonic

Magnitude 1/4

Harmonics

+

+

+

.

.